Joint arthroplasty is a well-known surgical procedure by which a diseased or damaged natural joint is replaced by a prosthetic joint. The prosthetic joint may include a prosthesis that is implanted into one or more of the patient's bones. Many hip prostheses include a femoral prosthesis that is implanted into a patient's femur. A femoral prosthesis typically includes a stem component that is received in the medullary canal of the patient's femur and a spherically-shaped head component that bears against the patient's acetabulum or a prosthetic replacement acetabular cup.
The elongated stem implant may be cemented into the medullary canal or may have a surface conducive for allowing the bone to heal directly to the implant. In some prostheses, the head component is attached to a neck of the stem component via a tapered trunnion. The acetabulum of the patient may also be reamed to receive a shell and a liner. A polyethylene, metal or ceramic liner with a metal shell is inserted into the acetabulum and acts as a socket for receiving the head component.